Solid materials (Conduction), liquids and gases (convection), and electromagnetic waves are all used to transport heat (radiation), and these three are the different types of heat.
The thermal energy transfer across a well-defined border is characterized as heat in physics.
The amount of work that a thermodynamic system can do is defined as its thermodynamic free energy. A joule is a measurement unit for energy, work, or heat.
Furthermore, The generation, utilization, conversion, and exchange of thermal energy (heat) across physical systems is the subject of heat transfer, which is a branch of thermal engineering.
Thermal Conduction, thermal convection, thermal radiation, and energy transfer via phase shifts are heat transfer methods.
To achieve heat transfer, engineers also address the transfer of mass of different chemical species (mass transfer in advection), either cold or hot.
Even though these mechanisms have separate properties, they frequently occur in the same system simultaneously.
In addition, Heat transfer, unlike state functions, is a process function (or path function); thus, the quantity of heat transferred in a thermodynamic process that changes the state of a system depends on how that process occurs.
Not just the net difference between the initial and final states of the process.
The modes of heat transport include thermal Conduction, thermal convection, and thermal radiation. So, please read on as we discussed the three different types of heat.
1. Conduction
Heat conduction happens on a tiny scale when hot, fast-moving, or vibrating atoms and molecules interact with surrounding atoms and molecules, transferring some of their energy (heat) to them.
This is one of the different types of heat. Heat is delivered through Conduction when adjacent atoms vibrate against one another or when electrons migrate from one atom to another.
Furthermore, Conduction is the most common heat transport method within a solid.
The study of heat transmission between solid bodies in contact is known as thermal contact conductance.
Also, Conduction is the process of heat transfer from one place to another without the movement of particles. Such as when placing a warm hand on a cold glass of water.
Heat is conducted from the warm skin to the cold glass. Still, little Conduction occurs if the hand is held a few inches away from the glass because air is a poor conductor of heat.
Furthermore, the change in temperature (a measure of heat energy) is zero in steady-state Conduction. The amount of heat entering a section equals the amount of heat leaving it.
The heat flow through the walls of a warm house on a cold day is an example of steady-state Conduction. The temperature inside the house is kept high.
In contrast, the temperature outside remains low. So the transfer of heat per unit time stays close to a constant rate determined by the insulation in the wall.
The spatial distribution of temperature in the walls will be approximately stable over time.
In a simple term, Conduction is most common in solids. To raise a pot of water to a boil on an electric stovetop, thermal energy is transferred from the hot burner to the excellent pot, causing the water’s temperature.
Conduction occurs as a result of molecular vibrations.
2. Convention
Heat transfer between a surface and a moving liquid or gas is referred to as convection, and this is one of the three types of heat. Convective heat transmission rises as the fluid or gas flows faster.
Natural and forced convection are the two types of convection. The heated atoms in the fluid cause natural convection. Which causes the fluid to travel higher toward the cooler particles in the air.
The fluid moves under the effect of gravity. For example, rising clouds of cigarette smoke or heat rising upwards from a car’s hood.
A fan, pump, or other external source forces the fluid to pass over the surface in forced convection.
In other words, Convective heat transfer, or simply convection, is the transfer of heat from one location to another through the flow of fluids.
Which is essentially the same as heat transfer via mass transfer. The fluid’s bulk motion improves heat transfer in many physical settings, such as between a solid surface and the fluid.
In liquids and gases, convection is the most common mode of heat transmission. Furthermore, convection is commonly used to represent the combined effects of heat conduction within the fluid (diffusion).
And heat transference via bulk fluid flow stream. At the same time, it is also described as the third form of heat transfer.
3. Radiation
The passage of heat across space is referred to as radiation (not to be confused with thermal radiation).
Radiation is a type of heat transfer that occurs without an intermediary medium; it can even work in and through a perfect vacuum.
For example, before heat is sent to the Earth, energy from the sun travels through space’s vacuum.
In other words, The transfer of energy via thermal radiation, i.e., electromagnetic waves, is known as radiant heat transfer. It can happen in a vacuum or any transparent substance (solid, fluid, or gas).
At temperatures above absolute zero, thermal radiation is emitted by all objects due to the random movement of atoms and molecules in matter.
Because these atoms and molecules are made up of charged particles (protons and electrons), their movement causes electromagnetic radiation to be emitted, which transfers energy away.
Radiation is only relevant for scorching items or objects with a huge temperature difference in most engineering applications.
